Cashmere or merino fine knit, I’d get a slightly sloppy one that falls off one shoulder. Not too long in the body, let it sit at your waist or very just below otherwise I think it will look too casual. Uniqlo have some nice merino jumpers.
Silk or satin t-shirt shape top, either tuck in or loose if it’s not too long.
The skirt is fitted so don’t go tight on top as well.
As it’s a dinner party, your top half will be on show more than the skirt when sitting down, so something with impact will be best, which is why I thought about a shimmery silk top or luxury knit.
With cream I’d look for a colour like oyster, pale pink, or gold/champagne.
I’ve got a skirt that shape and length in faux leather and I wear that sort of top (albeit in black or jewel colours as the skirt is black).